Sima Yang (Chinese: 司馬羕; 284[3] – 29 March 329[4]), courtesy name Yannian (延年),[5] was an imperial prince of the Jin dynasty.
In May 291, after the ouster and killing of Emperor Hui's first regent Yang Jun in April, Sima Liang was made co-regent with Wei Guan.
However, with the growing chaos in Northern China, he eventually had to abandon his fiefdom and follow Sima Yue, the Prince of Donghai and Emperor Huai's regent.
Together with Sima Zong, Yang was ordered to settle refugees to populate Zhongzhou (中州) and the remote areas of Jiangxi.
About two and a half months later, on 23 April, news of Emperor Min's execution reached Jiankang.
After Wang Dun, who had the upper hand in his struggle against Emperor Yuan, died in August 324 and his rebellion subsequently quelled, Sima Yang was made Grand Commandant in c.November.
[21][22] In early October 325, Emperor Ming became gravely ill; on 12 October, a number of high-level officials, including Sima Yang (who was then taizai), Yu Liang, Wang Dao, Bian Kun (卞壼), Xi Jian, Lu Ye (陸瞱; grandson of Lu Mao), and Wen Jiao formed the regency council.
Further, he became apprehensive of the generals Tao Kan and Zu Yue – neither of whom was mentioned in the list of honors and promotions announced by Emperor Ming's will and believed that Yu had erased their names from the will – and Su Jun, who had allowed many criminals to join his army.